In opening statements prosecutors said Gilberto "Lil' Mexico" Villarreal, 23, fired three shots as he was taken from a birthday party to which he wasn't invited, after fighting with the host.
Steven Moy, celebrating his 27th birthday, died from a gunshot wound to the leg. Yvette Espinoza and Juan Mendoza were also shot at the party but survived, the San Antonio Express-News said.
"Largely, with the help of MySpace, police tracked down Lil' Mexico," Assistant District Attorney Rita Spiegel said in court Tuesday. "He (Villarreal) finally admits he shot all three people, but by the way, did it in self-defense. This is not a case of self-defense."